1. Field of the Invention
The present invention relates to an apparatus and method for preventing illegal access to an electronic device by using a prohibit key, and more particularly, to an apparatus and method for preventing illegal access of an unauthorized user to an electronic device, by using a dynamically variable key.
2. Description of the Related Art
The rapid growth the of electronic field industry has brought about widespread use of electronic devices, and accordingly, people's concern and interest about the illegal access to the electronic devices and ways to protect personal information and property information stored and managed in electronic devices is higher than ever. Generally, in order to protect the personal information and information about user's property, a user of an electronic device sets a password known only to himself, so that access to a system and to his personal information and property information is only accepted when the preset password is correctly input.
However, the abovementioned way of accessing a system through inputting a password, has some drawbacks. If the password is exposed to the others or if someone attempts to crack the password the user may become a victim of identity theft. Accordingly, a variety of methods are being studied to protect a system from password exposure and malicious password cracking.
For example, one way to protect the system is to reject the illegal access of the other users, using a prohibit key. The use of the prohibit key has enabled not only the prevention of illegal access to the system, but also a report on such attempt to illegally access the system to a security personnel or authority to deal with the problem early so that user can be protected with more aggressive and active measures.
However, the use of prohibit key has a loophole and can endanger the security, if the prohibit key is exposed to the others. That is, if an unauthorized person who obtains prohibit the key tries to access the system, the chances to match the password are much higher because the unauthorized person can just combine the keys other than the prohibit key. For example, if the fact that number ‘9’ is set to a prohibit key is known to the unauthorized person, the possibility that the person will match the password by combining from 0 to 8 is higher than combining numbers all the way from 0 to 9.